... the bank used improper bidding strategies to squeeze excessive payments from the agencies that run the power grids in California and the Midwest in 2010 and 2011
...
improper trading practices were used at Houston-based JPMorgan Ventures Energy Corp.
...
JPMorgan Ventures Energy has contracts with power generating companies to trade their electricity.

FERC said the JPMorgan traders offered to sell electricity at artificially low prices in a "day-ahead" market, so that companies would put their plants on standby mode to quickly generate energy.

That would allow JPMorgan to earn fees for putting the power plants on standby mode.

Later, the traders would offer to sell electricity from the plants at higher prices in the market for last-minute energy needs, according to FERC.
...
A Senate committee held a hearing last week into whether banks should be allowed to control power plants, warehouses and oil refineries
...

| - - -- -

http://www.businessinsider.com/jpm-accused-of-energy-market-manipulation-2013-7
JP Morgan Accused Of Manipulating US Energy Markets Using 8 Different Trading Strategies

...
According to the report, it was specifically looking into the work of commodities legend Blythe Masters.

From NYT:

The regulatory document cites her supposed “knowledge and approval of schemes” carried out by a group of energy traders in Houston. The agency’s investigators claimed that Ms. Masters had “falsely” denied under oath her awareness of the problems and said that JPMorgan had made “scores of false and misleading statements and material omissions” to authorities, the document shows.
...
To add more drama to the story, in September the Fed will decide if it will continue to allow Wall Street banks to trade physical commodities at all. JP Morgan started entering the business aggressively after the financial crisis, and last week announced that it was considering making its exit as the risks may have become too great.
...